Monocrystal-like high-manganese hydroxide precursor, preparation method thereof and lithium-rich manganese-based positive electrode material

Abstract

The invention discloses a monocrystal-like high-manganese hydroxide precursor, a preparation method thereof and a lithium-rich manganese-based positive electrode material, and relates to the technical field of lithium ion battery materials. The monocrystal-like high-manganese hydroxide precursor comprises monocrystal-like particles or monocrystal particles formed by primary crystal grains; the primary crystal grain satisfies the following formula: lt; 001gt, 001gt; the thickness d in the direction is 50-800nm, lt; 010gt, 010gt; the length in the direction is 50-1000 nm, and the ratio d / of the thickness to the length meets 0.4 lt; d / lt; 1. By adding the phytic acid crystal face growth control agent, crystal lattice tilt is inhibited; 010gt, 010gt; growing in a direction such that lt; 001gt, 001gt; and lt; 010gt, 010gt; the preparation method has the advantages that the growth rate is close, and the monocrystal-like high-manganese hydroxide precursor and the anode material with large thickness / length ratio and less primary crystal grains are obtained, so that the pole piece has higher compaction density, high specific energy and excellent long cycle stability.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery materials technology, and in particular to a single-crystal high-manganese hydroxide precursor, its preparation method, and a lithium-rich manganese-based cathode material. Background Technology

[0002] While lithium-rich manganese-based cathode materials boast high specific energy, reaching up to 300 mAh / g, making them among the few high-specific-energy cathode materials, they still suffer from low electrode compaction density and low volumetric energy due to their low true density and large porosity. This low volumetric energy limit their applications in many scenarios, such as new energy vehicles, drones, and 3C consumer electronics.

[0003] Single crystallization is one of the most effective ways to improve electrode compaction and battery volumetric energy density. Traditional methods for single crystallization involve adding sintering aids to prepare single-crystal lithium-rich materials. However, these methods often suffer from poor capacity utilization, poor kinetics, uneven lithium distribution during the reaction leading to high polarization, poor rate capability, and poor cycling performance. Furthermore, the process is complex, typically requiring higher lithiation sintering temperatures, increasing energy consumption and cost. Additionally, powder crushing further increases equipment and process costs. Currently, the problems of low capacity, poor rate capability, and poor cycling performance in single-crystal lithium-rich manganese-based materials remain unsolved. Existing technologies for single crystallization, such as patent CN118811879A, involve adding niobium compounds during precursor co-precipitation, followed by high-temperature sintering and crushing to obtain single-crystal lithium-rich materials. However, the addition of expensive niobium compounds increases costs; the process is also complex and generates significant dust pollution. For example, patent CN116856058A first mixes a spinel phase compound with a lithium-containing compound to obtain a mixture, and then performs acid treatment to obtain a modified single-crystal material. This wet process is complex, costly, and has pollution issues. CN114284472B first obtains a precursor through co-precipitation, then sintersects it in air to form an oxide, then adds lithium oxide and silicate additives, and finally sintersects it after ball milling to obtain a silicate-modified single-crystal material. This also faces the problem of complex preparation processes and difficulty in scale-up. CN120319787A synthesizes a sodium oxide precursor first, and then exchanges it with a eutectic lithium compound; both face problems of high cost and difficulty in scale-up. Quasi-single-crystal materials combine the advantages of excellent polycrystalline kinetics and high capacity with the advantages of high compaction and high volumetric energy density of single-crystal electrodes. Therefore, quasi-single-crystal lithium-rich manganese-based materials possess both high mass specific energy and high volumetric specific energy, making them one of the preferred options for next-generation materials. For example, CN118676345A introduces additives when preparing a single-crystal lithium-rich manganese-based monocrystalline matrix, and subsequently modifies it by coating the manganese-rich single-crystal material with lithium cobalt phosphate, also using the method of adding flux; CN110391417B also uses the commonly used expensive Li2WO4 as a flux. CN117317210A adds one or more of Ta, Nb, W and / or Mo during the co-precipitation process to obtain primary particles with an average particle size of 400nm to 700nm to form single-crystal particles. The synthesis method is relatively complicated, and the use of expensive metal elements also increases the cost. CN117263267B synthesizes small-particle precursors via co-precipitation, followed by ultra-high temperature sintering at 950-1050℃ to obtain lithium-rich materials. However, it still faces challenges such as low tap density of secondary particle powder and thin and small average thickness of primary particles. Although it yields near-single-crystal lithium-rich materials with particle sizes of 300nm~800nm, it also suffers from low capacity and low initial efficiency. The samples also exhibit problems such as excessive enrichment reactions, high gas production, and poor cycling performance during the cycling process.It is evident that existing single-crystal or near-single-crystal lithium-rich manganese-based technologies are prepared by adding expensive and heavy sintering aids. The prepared lithium-rich materials still face problems such as low capacity, low initial efficiency, poor cycle life, and high cost.

[0004] Synthesizing near-monocrystalline manganese-based hydroxide precursors to prepare near-monocrystalline lithium-rich manganese-based materials without using precious metal additives is a low-cost and advanced technological route, but related technological inventions are currently lacking. This is because the surface energy of the (001) crystal facet of manganese-based hydroxides is much lower than that of the active {010} crystal facet. The high surface energy {010} crystals preferentially grow, typically resulting in thin, lamellar primary grains with high crystal surface energy barriers. These traditional thin-film precursor structures are difficult to use to prepare single-crystal or near-monocrystalline lithium-rich manganese-based cathode materials. Therefore, preparing near-monocrystalline hydroxide precursors by controlling the growth rate of crystal faces is feasible, but such technology is currently unavailable. Summary of the Invention

[0005] One of the objectives of this invention is to provide a single-crystal high-manganese hydroxide precursor, which has a large primary grain thickness-to-length ratio, solving the problem of low volumetric energy density of lithium-rich manganese-based materials, and possessing high specific energy density and excellent long-cycle stability.

[0006] The second objective of this invention is to provide a method for preparing this type of single-crystal high-manganese hydroxide precursor.

[0007] The third objective of this invention is to provide a lithium-rich manganese-based cathode material prepared from this type of single-crystal high-manganese hydroxide precursor.

[0008] The fourth objective of this invention is to provide an application of the lithium-rich manganese-based cathode material in liquid or solid lithium batteries.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a precursor of a quasi-single-crystal high-manganese hydroxide, comprising quasi-single-crystal particles or single-crystal particles formed by primary grain formation. The primary grain satisfies: <001> Orientation thickness d In the 50-800nm ​​range, <010> Directional length The thickness is between 50-1000 nm, and the thickness-to-length ratio is... d / Satisfying 0.4 < d / <1.

[0010] Preferably, the primary grains satisfy: <001> Orientation thickness d In the 300-500nm range, <010> Directional length Within 500-80nm, and the thickness to length ratio d / At 0.55 - 0.85.

[0011] Furthermore, the median particle size D50 of the quasi - single - crystal manganese hydroxide precursor satisfies 0.8μm < D50 < 10μm, preferably 0.8μm < D50 < 2μm.

[0012] The chemical general formula of the quasi - single - crystal manganese hydroxide precursor is Mn x Ni y Co z (OH)2, where x > 0.5, 0.15 < y < 0.4, 0 ≤ z ≤ 0.17, and x + y + z = 1, including but not limited to Mn 0.65 Ni 0.33 Co 0.02 (OH)2, Mn 0.66 Ni 0.26 Co 0.08 (OH)2, Mn 0.65 Ni 0.35 (OH)2, Mn 0.75 Ni 0.25 (OH)2, Mn 0.67 Ni 0.28 Co 0.05 (OH)2, etc.

[0013] Preferably, the quasi - single - crystal particles are secondary particles formed by several to dozens of primary grains.

[0014] In a second aspect, the present invention provides a method for preparing the above - mentioned quasi - single - crystal manganese hydroxide precursor, comprising the following steps: (1) The reaction kettle (5 - 3000L) is kept at a constant temperature of 45 - 60°C. First, add the bottom liquid with a volume of 1 / 3 of the reaction kettle, adjust the pH of the bottom liquid between 11.3 - 13.5, introduce an inert gas, turn on the stirring motor, and stir at a speed of 400 - 950 rpm; (2) Add the metal salt mixed solution, the mixed solution containing a complexing agent, a crystal - face growth controller, and a surfactant (i.e., the complexing agent, the crystal - face growth controller, and the surfactant are dissolved in one tank) and the precipitant solution into the reaction kettle for crystal growth co - deposition reaction; (3) After the reaction is completed, carry out aging and static settling, then filter, wash, and dry to finally obtain the quasi - single - crystal manganese hydroxide precursor

[0015] The following is a detailed description: In step (1), the bottom liquid is water, and the pH of the bottom liquid is adjusted between 11.3 - 13.5 with a NaOH solution; In step (2), the metal salts include nickel salts, cobalt salts, and manganese salts; the nickel salt is selected from one or more of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate; the cobalt salt is selected from one or more of cobalt sulfate, cobalt chloride, cobalt nitrate, and cobalt acetate; the manganese salt is selected from one or more of manganese sulfate, manganese chloride, manganese nitrate, and manganese acetate; the total concentration of metal ions in the mixed metal salt solution is 0.5-2.2 mol / L; The complexing agent in step (2) is selected from one or more of ammonia, ammonium bicarbonate, and ammonium carbonate; the crystal growth control agent is selected from one or more of phytic acid, lithium phytate, sodium phytate, potassium phytate, zinc phytate, and aluminum phytate; the surfactant is a benzene sulfonate anionic surfactant, preferably sodium dodecylbenzene sulfonate. The concentration of the complexing agent in the mixed solution is 0.02~1 g / L; the concentration of the crystal face growth control agent is 0.001~10 g / L, preferably 1~4 g / L; and the concentration of the surfactant is 0.001~10 g / L, preferably 2~4 g / L. The precipitant in step (2) is one or more selected from sodium hydroxide and potassium hydroxide; the concentration of the precipitant in the precipitant solution is 2-8 mol / L, preferably 4-6 mol / L.

[0016] In step (2), the addition method can be a one-time addition, a batch intermittent addition, or a continuous addition.

[0017] Preferably, in step (2), the metal salt mixed solution, the mixed solution containing the complexing agent, the crystal face growth control agent, and the surfactant, and the precipitant solution are continuously pumped into the reactor at a certain flow rate ratio; wherein the flow rate of the metal salt mixed solution is 0.2-3 L / h, preferably 0.5-1.5 L / h, more preferably 0.8 L / h; the flow rate of the mixed solution containing the complexing agent, the crystal face growth control agent, and the surfactant is 0.05-5 L / h, preferably 0.08 L / h; and the pH of the reaction system is adopted. PID The ratio (proportional-integral-derivative) is controlled at 11-12; the reaction temperature is 45-60℃; the stirring speed is 500-1000 rpm; and the reaction time is 10-100h. In step (3), the aging temperature is 40-60℃, preferably 45-55℃, and the aging time is 1-48h, preferably 10-24h; the drying temperature is 100-120℃ and the drying time is 10-15h.

[0018] Thirdly, the present invention provides a lithium-rich manganese-based cathode material, which is prepared by mixing and sintering the above-mentioned single-crystal high-manganese hydroxide precursor with a lithium source.

[0019] The molecular formula of the single-crystal cathode material is Li 1+a (Mn x Niy Co z ) 1-a O2, where 0.1 < a ≤ 0.25.

[0020] Weigh the precursor and lithium salt Li2CO3 according to the stoichiometric ratio and mix them evenly using a high-speed mixer. Lithification sintering process: A segmented continuous sintering process is adopted. Under air or oxygen-enriched air atmosphere, the temperature is increased at a rate of 3-5℃ / min and held at 450-550℃ for 3-5 hours. Then, the temperature is increased at the same rate and held at 850-940℃ for 10-25 hours. After that, the material is naturally cooled to room temperature to obtain lithium-rich manganese-based cathode material.

[0021] The electrode compaction density of lithium-rich manganese-based cathode material is ≥3.1 g / cm³. 2 .

[0022] Fourthly, this invention provides an application of the above-mentioned lithium-rich manganese-based cathode material in liquid or solid-state lithium batteries. The battery can be cylindrical, pouch, prismatic, or blade-shaped, and its shape is not limited.

[0023] Beneficial effects: This invention utilizes phytic acid-based crystal facet growth control agents, such as phytic acid, sodium phytate, lithium phytate, and aluminum phytate, along with anionic surfactants. Phytic acid, a cyclic polyol phosphate ester / salt, exhibits a particularly strong chelating ability for metal ions to reduce the surface energy of the (010) crystal facet. Benzenesulfonic acid-based surfactants induce the enrichment of metal ions on the crystal facet. Together, these two agents inhibit lattice deformation. <010> Directional growth, making <001> and <010> With similar growth rates, the formation of wide / long primary grains is suppressed. By controlling the morphology, thickness-to-length ratio, and number of primary grains in the precursor, a near-single-crystal high-manganese hydroxide precursor with a large thickness-to-length ratio and fewer primary grains is obtained. Then, a simple sintering process is used to obtain a near-single-crystal lithium-rich manganese-based material. The obtained near-single-crystal lithium-rich manganese-based material not only gives the electrode a high compaction density, reaching up to 3.4 g / cm³, but also... 3 This material approaches high-nickel ternary cathode materials, solving the problem of low volumetric energy density in lithium-rich manganese-based materials. Furthermore, it possesses high specific energy and excellent long-cycle stability, balancing high specific energy density and high volumetric energy density. It exhibits good processing performance and is easy to sieve. A larger primary grain thickness / length ratio and smaller secondary particle specific surface area suppress oxygen evolution side reactions during lithium battery cycling. The single-crystal / quasi-single-crystal lithium-rich manganese-based cathode material demonstrates excellent cycle life at high voltages (initial efficiency improved from 76% to over 80%, capacity retention improved from 82% to over 85%).

[0024] The method of this invention avoids the introduction of expensive precious metals and higher sintering temperatures in single crystal / quasi-single crystal processes, thereby reducing the cost of preparing single crystal lithium-rich manganese-based materials.

[0025] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments. Attached Figure Description

[0026] Figure 1 Schematic diagrams of traditional sheet-like precursors and the single-crystal precursors of this invention; Figure 2 The image shows the morphology of the precursors in the comparative example and Example 1.

[0027] Figure 3 This is a morphology diagram of the single-crystal lithium-rich manganese-based cathode material of Example 1.

[0028] Figure 4 The first charge-discharge curves are for comparative examples and embodiments; Figure 5 Cyclic stability plots for comparative examples and embodiments. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0030] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0031] Comparative Example Preparation of polycrystalline high-manganese hydroxide precursor: Mn was first synthesized by hydroxide coprecipitation. 0.66 Ni 0.26 Co 0.08 (OH)2. The specific steps are as follows: Prepare a mixed solution of nickel sulfate, manganese sulfate, and cobalt sulfate with a total metal ion concentration of 2M according to the stoichiometric ratio; prepare an ammonia complexing agent with an ammonia concentration of 0.5 g / L; and prepare a precipitant solution of 6 mol / L NaOH.

[0032] The 100L reactor was kept at a constant temperature of 50℃. First, a bottom liquid (water) was added, filling 1 / 3 of the reactor volume. The solution was adjusted to 12.5 using NaOH solution. Inert gas was introduced for 2 hours. The stirring motor was then turned on, and the mixture was stirred at 450 rpm. The three liquids were pumped into the reactor at appropriate flow rates: the metal salt mixture flow rate was 0.6 L / h, and the ammonia flow rate was 0.08 L / h. The NaOH solution was... PIDThe pH was controlled at 11.5 using a proportional-integral-derivative (PI-DI) control program. Particle growth was monitored by sampling throughout the process until particle morphology, sphericity, and D50 were measured. Feeding was then stopped, and the particles were allowed to stand for 6 hours. After washing, filtration, and drying, the polycrystalline high-manganese hydroxide precursor was obtained.

[0033] Material sintering: according to stoichiometry (Li 1.18 Mn 0.66 Ni 0.26 Co 0.08 O2) Weigh the precursor and lithium salt Li2CO3, mix them evenly with a high-speed mixer, and perform the sintering process: heat at 550℃ for 5 hours at a heating rate of 5℃ / min, then heat at 910℃ for 15 hours at the same heating rate, and then allow to cool naturally to room temperature to obtain the lithium-rich manganese-based cathode material Li. 1.18 (Mn 0.66 Ni 0.26 Co 0.08 )O2.

[0034] Electrode preparation and compaction density measurement method: Slurry mixing ratio: Positive electrode material: PVDF: Conductive carbon = 95:2.5:2.5; Weigh the materials according to the ratio and prepare the slurry in a homogenizer. Coating, drying, cutting, and rolling. Electrode compaction density = (Electrode weight - Aluminum foil weight) 0.95 / (Electrode thickness - Aluminum foil thickness) (Electrode area).

[0035] Electrochemical performance testing: The electrochemical performance of the prepared lithium-rich material was evaluated using a coin cell. The negative electrode was a lithium metal sheet, and the electrolyte volume ratio was EC:DMC:FEC=35:55:10. The test was conducted using the Blue Battery testing system, with the charge / discharge current set at 1C=200mAh / g and the voltage window at 2.0-4.8V.

[0036] Example 1 Preparation of single-crystal-like high-manganese hydroxide precursor: Mn was first synthesized by hydroxide coprecipitation. 0.66 Ni 0.26 Co 0.08 (OH)2. The specific steps are as follows: Prepare a mixed solution of nickel sulfate, manganese sulfate, and cobalt sulfate with a total metal ion concentration of 2M according to stoichiometric ratio; prepare a mixed solution of ammonia water, phytic acid, and sodium dodecylbenzenesulfonate with a concentration of 0.5 g / L, phytic acid concentration of 1 g / L, and sodium dodecylbenzenesulfonate concentration of 2.5 g / L; prepare a 6 mol / L NaOH solution as a precipitant.

[0037] The 100L reactor was kept at a constant temperature of 50℃. First, a bottom liquid (water) was added, filling 1 / 3 of the reactor volume. The solution was adjusted to 12.5 using NaOH solution. The stirring motor was turned on, and inert gas was introduced for 2 hours, with stirring at 450 rpm. The above liquids were then pumped into the reactor at appropriate flow rates and speeds: the flow rate of the metal salt mixture was 0.6 L / h, and the flow rate of the mixed solution of ammonia, phytic acid, and sodium dodecylbenzenesulfonate was 0.08 L / h. The NaOH solution was prepared using… PID The (proportional-integral-derivative) control program maintains the liquid pH at 11.5 with a control accuracy of ±0.02. Process sampling monitors particle growth; once particle morphology, sphericity, thickness-to-length ratio, and D50 reach the expected values ​​of 1.5 micrometers, feeding is stopped, and the mixture is allowed to age and stand for 6 hours. After washing, filtration, and drying, a near-single-crystal high-manganese hydroxide precursor, Mn, is obtained. 0.66 Ni 0.26 Co 0.08 (OH)2.

[0038] Material sintering: The precursor and lithium salt Li₂CO₃ were weighed according to stoichiometry and mixed evenly using a high-speed mixer. Sintering process: The temperature was increased by 5℃ / min and held at 550℃ for 5 hours, then increased by the same rate and held at 910℃ for 15 hours. After natural cooling to room temperature, a near-single-crystal lithium-rich manganese-based cathode material Li₂CO₃ was obtained. 1.18 (Mn 0.66 Ni 0.26 Co 0.08 )O2.

[0039] The electrode preparation and electrochemical performance testing are the same as described above.

[0040] Use SEM to characterize product morphology. Figure 2The comparative precursor appears as secondary particles composed of numerous thin flakes. <001> The directional thickness is 60-200nm. <010> The axial length is as high as 2000 nm. The thickness-to-length ratio of the thin film is approximately 0.1. In Example 1, the appearance morphology underwent a significant change, from... <001> The thickness increases in the longitudinal direction, reaching 350-500 nm, typically around 400 nm, while the length decreases to 500-700 nm, achieving a thickness-to-length ratio of approximately 0.6-0.7, with a typical value of around 0.6. The number of primary particles decreases, ranging from a few to dozens to form secondary single-crystal particles. It is evident that the addition of phytic acid, a crystal growth control agent, successfully reduces the surface energy of the {010} crystal plane, inhibiting its growth rate. This allows its growth rate to be more consistent with... <001> The directions are similar. Ultimately, primary particles with a large thickness-to-length ratio (closer to 1) are obtained. Moreover, because these particles have a large exposed active crystal facet, they are highly active and easily overcome the interfacial barrier during high-temperature sintering. They can then mature and absorb smaller particles at lower temperatures to continue growing into near-single-crystal or even single-crystal particles. This avoids the need for expensive metal additives such as niobium and tungsten. Therefore, it is a low-cost method for preparing near-single-crystal and single-crystal lithium-rich materials.

[0041] like Figure 3 As shown, a near-single-crystal lithium-rich manganese-based cathode material was successfully prepared from a near-single-crystal precursor.

[0042] The electrochemical performance of lithium-rich manganese-based cathode materials with this structure will be greatly improved: First, there is the initial coulomb efficiency, such as Figure 4 As shown in Table 1, the initial efficiency of the comparative example was increased from 76% to over 80%. The 1C specific capacity increased from 189.3 mAh g⁻¹ in the comparative example. -1 Increased to 191.8 mAh g -1 .

[0043] Excellent cycling performance, as shown in Table 1 and Figure 5 As shown, the initial 1C discharge capacity of the comparative polycrystalline sample is 189.3 mAh g. -1 After 500 cycles, it decreased to 156.6 mAh g. -1 The capacity retention rate was only 82.73%; while the quasi-single-crystal sample prepared in Example 1 showed an increased 1C discharge capacity of 191.8 mAh g⁻¹. -1 After 500 cycles, there is still 166.9 mAh g. -1 The capacity retention rate is as high as 87.02%, indicating that the quasi-single-crystal lithium-rich manganese-based cathode material obtained by this method has excellent capacity utilization and cycle stability.

[0044] Example 2 The precursor preparation method and material sintering preparation method were the same as in Example 1, except that the crystal growth control agent was replaced with sodium phytate, while the concentration remained unchanged. The obtained precursor had a D50 of 1.5 micrometers. In subsequent examples, the D50 was controlled to be 1.5 micrometers. d / The values ​​range from 0.62 to 0.8. Electrochemical and compaction properties are shown in Table 1 and... Figure 5 As shown, the capacity retention rate after 500 cycles is 85.08%.

[0045] Example 3 The precursor preparation method and material sintering preparation method are the same as in Example 1, except that the crystal growth control agent is replaced with aluminum phytate, while the concentration remains unchanged. The obtained precursor... d / The value is between 0.55 and 0.65. Electrochemical and compaction properties are shown in Table 1 and... Figure 5 As shown, the capacity retention rate after 500 cycles is 85.15%.

[0046] Example 4 The precursor preparation method and material sintering preparation method are the same as in Example 1, except that the crystal growth control agent is replaced with lithium phytate, while the concentration remains unchanged. The obtained precursor... d / The value ranges from 0.6 to 0.7. Electrochemical and compaction properties are shown in Table 1, with a capacity retention of 86.8% after 500 cycles.

[0047] Example 5 The precursor preparation method and material sintering preparation method are the same as in Example 1, except that the crystal growth control agent is replaced with sodium phytate at the same concentration, and the surfactant concentration of sodium dodecylbenzenesulfonate is increased to 4 g / L. The obtained precursor morphology is more cubic. d / The value ranges from 0.7 to 0.8. Electrochemical and compaction properties are shown in Table 1, with a capacity retention of 83.6% after 500 cycles.

[0048] Example 6 The precursor preparation method and material sintering preparation method are the same as in Example 1, except that the crystal growth control agent is replaced with sodium phytate, and the concentration is increased to 4 g / L. The obtained precursor... d / The value ranged from 0.75 to 0.84. Electrochemical and compaction properties are shown in Table 1, with a capacity retention of 86.2% after 500 cycles.

[0049] Table 1. D50, thickness-to-length ratio, electrochemical properties and compaction results

[0050] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A precursor for a single-crystal high-manganese hydroxide, characterized in that, Containing quasi-single crystal particles or single crystal particles formed by one-time grain formation; The primary grain satisfies: <001> Orientation thickness d In the 50-800nm ​​range, <010> Directional length The thickness is between 50-1000 nm, and the thickness-to-length ratio is... d / Satisfying 0.4 < d / <1.

2. The quasi-single-crystal high-manganese hydroxide precursor according to claim 1, characterized in that, The primary grain satisfies: <001> Orientation thickness d In the 300-500nm range, <010> Directional length Within 500-800nm, and the thickness to length ratio d / Between 0.55 and 0.

85.

3. The quasi-single-crystal high-manganese hydroxide precursor according to claim 1, characterized in that, The median particle size D50 of the quasi-single crystal manganese hydroxide precursor satisfies 0.8 μm < D50 < 10 μm, preferably 0.8 μm < D50 < 2 μm.

4. The quasi-single-crystal high-manganese hydroxide precursor according to claim 1, characterized in that, The chemical general formula of the quasi-single crystal manganese hydroxide precursor is Mn x Ni y Co z (OH)2, where x > 0.5, 0.15 < y < 0.4, 0 ≤ z ≤ 0.17, and x + y + z = 1.

5. A method for preparing a single-crystal-like high-manganese hydroxide precursor according to any one of claims 1-4, characterized in that, Comprising the following steps: (1) The reaction kettle is kept at a constant temperature of 45 - 60 °C. First, add the bottom liquid with a volume of 1 / 3 of the reaction kettle, adjust the pH of the bottom liquid between 11.3 - 13.5, introduce an inert gas, turn on the stirring motor, and stir at a speed of 400 - 950 rpm; (2) Add the metal salt mixed solution, the mixed solution containing a complexing agent, a crystal face growth control agent, and a surfactant, and a precipitant solution into the reaction kettle to conduct a crystal growth co-deposition reaction; (3) After the reaction is completed, carry out aging and static settlement, then carry out filtration, washing, and drying to finally obtain the quasi-single crystal manganese hydroxide precursor.

6. The preparation method according to claim 5, characterized in that, In step (2), the metal salts include nickel salts, cobalt salts, and manganese salts; the nickel salts are one or more selected from nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate; the cobalt salts are one or more selected from cobalt sulfate, cobalt chloride, cobalt nitrate, and cobalt acetate; the manganese salts are one or more selected from manganese sulfate, manganese chloride, manganese nitrate, and manganese acetate; the total concentration of metal ions in the metal salt mixed solution is 0.5 - 2.2 mol / L; In step (2), the complexing agent is one or more selected from ammonia water, ammonium bicarbonate, and ammonium carbonate; the crystal face growth control agent is one or more selected from phytic acid, lithium phytate, sodium phytate, potassium phytate, zinc phytate, and aluminum phytate; the surfactant is an anionic surfactant of benzene sulfonate type, preferably sodium dodecyl benzene sulfonate; The concentration of the complexing agent in the mixed solution is 0.02 - 1 g / L; the concentration of the crystal face growth control agent is 0.001 - 10 g / L, preferably 1 - 4 g / L; the concentration of the surfactant is 0.001 - 10 g / L, preferably 2 - 4 g / L; In step (2), the precipitant is one or more selected from sodium hydroxide and potassium hydroxide; the concentration of the precipitant in the precipitant solution is 2 - 8 mol / L.

7. The preparation method according to claim 5, characterized in that, 8. The preparation method according to claim 5, characterized in that, The conditions for the co-precipitation reaction include: the flow rate of the metal salt mixed solution is 0.2 - 3 L / h, the flow rate of the mixed solution containing a complexing agent, a crystal face growth control agent, and a surfactant is 0.05 - 5 L / h; the pH of the reaction system is 11 - 12, the reaction temperature is 45 - 60 °C, the stirring speed is 500 - 1000 rpm, and the reaction time is 10 - 100 h.

9. A lithium-rich manganese-based cathode material, characterized in that, In step (3), the aging temperature is 40 - 60 °C, the aging time is 1 - 48 h; the drying temperature is 100 - 120 °C, and the drying time is 10 - 15 h. Prepared by mixing and sintering the quasi-single crystal manganese hydroxide precursor described in any one of claims 1 - 4 or the quasi-single crystal manganese hydroxide precursor prepared by the preparation method described in any one of claims 5 - 8 with a lithium source.

10. An application of the lithium-rich manganese-based cathode material described in claim 9 in a liquid or solid lithium battery.

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